A combination lock as referred to in the art, is a lock which eliminates the use of a key for opening it. For opening such locks there is typically provided a single dial which should be rotated several times in different directions to reach the correct number forming the combination or by a plurality of dials in which each should be rotated to a position in which the correct combination number appears, or by a plurality of push-buttons which should be pressed in a correct sequence, to reach the right opening combination. The code which enables opening of the lock is at times referred to as a combination code, or an opening code.
A first disadvantage of heretofore known locks resides in that the locking mechanism is arranged in series, i.e. in order to render the locking mechanism some complication, it usually comprises three or more locking assemblies, each of which being separately handled. This arrangement results in that each locking assembly being successfully manipulated into its opening position, renders the picking procedure easier. Even single dial combination locks, although comprising only one manipulating dial, comprise three or more locking assemblies, which are handled in series.
Still a further drawback with prior art locks is the mechanical complexity requiring a plurality of elements, each adapted for manipulating a single locking assembly of a locking mechanism. Furthermore, locking mechanism arranged in series, also require more time for opening.
In addition, in some combination locks, the lock remains unlocked, even if it is closed (the shackle being introduced into its opening within the padlock, or the door of a safe being closed) until positive displacement of at least one manipulating member.
Even more so, most locks require visual contact with the lock to establish manipulation thereof. Obviously, such a requirement may be problematic for blind people or in conditions of darkness. Additionally, in may events it might be required to enable manipulation of a lock using a single hand. Such locks are suitable, in particular for invalids etc. Many other types of locks, in particular security locks, are electrically or electronically operated, the drawbacks of which being obvious.
Known combination or key-less locks are described, for example, in U.S. Pat. Nos. 2,049,983, 2,830,447, 2,931,204, 4,476,698, 4,733,548, 5,109,684 and 5,267,460. However, it is considered that neither of these patents provides an adequate solution for the above referred to drawbacks. U.S. Pat. No. 2,491,779 discloses a combination lock comprising four actuating pins of different lengths, each adapted for engagement in turn with a corresponding lever of the four discs. A manipulating plate displaces each time only one of the levers, thus entailing angular displacement of a single disc at a time to the extent of one notch at a time.
It is the object of the present invention to provide a combination lock mechanism, in which the above referred to disadvantages are significantly reduced or overcome and which allow easy manipulation of the lock single handed and without visual contact with the lock.